Moisture protection - essential for every building

Moisture protection prevents internal moisture-laden air from escaping through joints and cracks, to condense within the building structure and cause damage. To avoid this, the building shell must be protected with materials that fulfil all of the requirements for airtightness.


Lightweight and timber constructions

For moisture protection in lightweight and timber constructions, it is important that the outer surface of the construction is wind-tight and the inner surface airtight.

ISOVER’s INTEGRA ECRAN is recommended as a particularly stable underlay and sarking membrane, for full wind proofing,

For interior airtightness, use VARIO KM or VARIO KM Duplex UV fixed with compatible adhesive and sealing products.


Solid wall constructions

In solid wall constructions with external thermal insulation, the interior plaster lining, windows and doors form the airtight layer.

Where renovation involves the installation of insulation to the interior of the structure, the airtight layer must be on the inner, warm side of the structure.

ISOVER VARIO products can provide an effective airtight layer, and will help to secure the longevity of your property thanks to their excellent moisture protection.

How wet is air

The warmer the air, the more water vapour it can contain. At 30°C, for instance, water vapour content is approximately 30 g/m3, whilst at 0°C it is just 5 g/m3, and at -10° C no more than 2 g/m3. In a 10 m² room at 30°C with a 2.5 m ceiling height, approximately 750 g of water vapour is present in the air.

Damages caused by wet air

Leaks are a potential cause of damage in a building. When damp, warm air moves through gaps and cracks from the interior into colder areas of the un-protected building, the vapour it contains can condense into water. This provides an ideal habitat for moulds and other fungi.

The affected material can suffer damage and insulation performance can be reduced by up to a sixth, leading to further dampness and setting in motion a chain reaction that leads to serious damage.

The requirements of airtightness materials

Generally, materials used to produce flat surfaces are airtight (foils, plaster, etc.).

All materials, particularly ceiling membranes and adhesives, must be compatible and selected to work together.

UV and moisture resistance are important, as is tear resistance. In cold regions, where the airtight layer is applied to the warm side of the building, the materials must also be water vapour retardant.